What blind people are discussed?
Rav Sadya Gaon: They moved like blind people. Ibn Ezra - [the prefix Kaf is omitted,] like "Esh Ocheles Hu" (Devarim 4:24. Hashem is like fire.)
Rashi: They are blind people who walked in the market.
Ri Kara: One who was wounded on his head, the blood drips on his eyes and he cannot see, as if he is blind.
Palgei Mayim: They are blind in Da'as (ignorant), like it says "v'Lifnei Iver Lo Siten Michshol" (Vayikra 19:14).
Why does it say "ba'Chutzos"?
Palgei Mayim: They sinned overtly, and no one protested against them. Yerushalayim was destroyed because they did not protest against each other (Shabbos 55a).
What is the meaning of "Nego'alu ba'Dam"?
Rashi: Their feet slipped on the blood of people that the Resha'im killed in the market.
Ibn Ezra, Ri Kara, Rid: They became dirty from blood 1 .
Palgei Mayim: They stumbled so much to the point that they became defiled via murder.
Ibn Ezra: The blood was from the dead. Ri Kara implies that it was from their own wounds. (PF)
Why could they not touch their garments?
Rav Sadya Gaon: They became dirty from blood to the point that they could not touch their garments.
Rashi: They became dirty to the point that people near them could not touch their garments.